#include <iostream>
int main(){
    // if(condition) first code;
    if(1<0)
        std::cout<<"1>0 ok!";std::cout<<"OK!";

    // if(...) { codes; }
    if(3>2){// '\n' => enter换行
        std::cout<<"\n3";
        std::cout<<">2";
    }
    return 0;
}